They can inflate and then they can do three things, do a huge jump that will deflate them, float/glide, and do a knockback attack that is similar to the diplodocus' only attack. They can also seat more than one person at a time

Keeping oxygen in reserve prevents fall damage

Inhale to increase damage resistance, get a decent level saddle, back up slowly into turrets, tank all of the enemy's turrets

Apparently they are supposed to be like a hot air ballon from what i heard, you load it up to almost encumberation and have it inflate like the fat caterpillar it is